我们手里有一份Android系统的源码，那你如果想知道这份源码是哪个版本的，该怎么办呢？

查找代码：

/build/core/version_defaults.mk

在文件中查找PLATFORM_VERSION，你就会发现如下段代码：

1
2
3
4
5
6
7
ifeq "" "$(PLATFORM_VERSION)"
  # This is the canonical definition of the platform version,
  # which is the version that we reveal to the end user.
  # Update this value when the platform version changes (rather
  # than overriding it somewhere else).  Can be an arbitrary string.
  PLATFORM_VERSION := 7.0
endif

这里边的PLATFORM_VERSION := 7.0就是当前代码系统版本。

不同的版本代码稍有差别，但总体**PLATFORM_VERSION **这个关键字是没差别的，搜索就对了。

Android 10 源码：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
# Note that there should be one PLATFORM_VERSION and PLATFORM_VERSION_CODENAME
# entry for each unreleased API level, regardless of
# MIN_PLATFORM_VERSION/MAX_PLATFORM_VERSION. PLATFORM_VERSION is used to
# generate the range of allowed SDK versions, so it must have an entry for every
# unreleased API level targetable by this branch, not just those that are valid
# lunch targets for this branch.
PLATFORM_VERSION.QP1A := 10

# These are the current development codenames, if the build is not a final
# release build.  If this is a final release build, it is simply "REL".
PLATFORM_VERSION_CODENAME.QP1A := REL

ifndef PLATFORM_VERSION
  PLATFORM_VERSION := $(PLATFORM_VERSION.$(TARGET_PLATFORM_VERSION))
  ifndef PLATFORM_VERSION
    # PLATFORM_VERSION falls back to TARGET_PLATFORM_VERSION
    PLATFORM_VERSION := $(TARGET_PLATFORM_VERSION)
  endif
endif
.KATI_READONLY := PLATFORM_VERSION

关键字PLATFORM_VERSION.QP1A := 10表明当前源码版本是Android 10的。